UC Santa Barbara

Children use a number of cues to infer friendship. For instance, children believe that people who are similar, spend time together, and are loyal to each other are friends (Liberman & Shaw, 2019). Here, in two studies (total N = 524), we investigated whether 4- to 12-year-old children infer friendship using a novel cue: managing someone's reputation by correcting them in private. Children were asked whether an agent was better friends with a person they corrected in public, or one they corrected in private. Both younger (4- to 7-years-old) and older (8- to 12-years-old) children inferred stronger friendship between the agent and the privately corrected character (Study 1). In a second study, we asked whether an agent was better friends with a person they corrected in private, or a person who shared a different friendship cue (similarity, propinquity, loyalty). With age children became more likely to privilege private correction, and children who were attentive to the task expected private correction to be a stronger friendship cue than similarity (Study 2). These findings suggest that concerns for others' reputations may play an important role in friendships, and protecting another person's reputation may be increasingly indicative of friendship with development.

Abstract: We show that, contrary to the ordinary Chow groups, the canonical map from the Chow group of 0-cycles with modulus on a $d$-dimensional smooth variety $X$ with an effective divisor $D$ over a field to the $(2d,d)$-th Nisnevich motivic cohomology of $X$ relative to $D$ is not always an isomorphism. This is achieved by showing that the degree zero part of the motivic cohomology with modulus over a finite field is isomorphic to the geometric part of an abelian étale fundamental group with modulus.

Anaerobes thrive in the absence of oxygen and are an untapped reservoir of biotechnological potential. Therefore, bioprospecting efforts focused on anaerobic microbial diversity could rapidly uncover new enzymes, pathways, and chassis organisms to drive biotechnology innovation. Despite their potential utility, anaerobic fermenters are viewed as inefficient from a biochemical perspective because their metabolisms produce fewer ATP (~2) per molecule of glucose processed than heterotrophic respirers (~32–38 ATP). While aerobes excel at ATP generation, they are often less efficient than anaerobes at processes that compete with ATP generation for cellular resources. This perspective highlights how anaerobic adaptations are advantageous for synthetic biology and biomanufacturing applications through the engineering of microbial cell factories. We further highlight emerging applications of anaerobic bioprocessing, including the use of anaerobic metabolisms for lignocellulosic bioprocessing, human and environmental health, and value-added bioproduction.

Abstract: In this mixed methods study, we analyzed survey and interview data from 100 preservice secondary science and mathematics teachers enrolled in four teacher education programs (TEPs) to investigate their readiness to teach multilingual learners. We defined readiness as preservice teachers' sense of preparedness to teach multilingual learners and their understanding of effective multilingual learner instruction. We examined participants' self‐reported levels of preparedness, their understanding of effective multilingual learner instruction, and sources contributing to and/or limiting their readiness. We found that participants' readiness to teach multilingual learners significantly increased between the beginning and end of their TEPs. We also found that participants' understanding of effective multilingual learner instruction was significantly associated with a higher sense of preparedness. Furthermore, we found that participants enrolled in graduate TEPs reported higher levels of preparedness than participants enrolled in an undergraduate TEP. Likewise, participants whose first language was other than or in addition to English reported higher levels of preparedness. Finally, participants identified field placement experiences, personal and professional background, and coursework as factors contributing to their readiness to teach multilingual learners. We close with recommendations for teacher educators intent on helping preservice teachers better understand and implement effective instruction for multilingual learners.

Abstract: Nearby blue compact dwarf galaxies (BCDs) are considered analogs to objects from the Epoch of Reionization revealed by JWST, having similarly low stellar masses, low metallicities, and high specific star formation rates. Thus, they represent ideal local laboratories for detailed multiwavelength studies of their properties and mechanisms that shape them. We report the first JWST MIRI/MRS observations of the BCD SBS 0335-052 E, analyzing MIR emission lines tracing different levels of ionization (e.g., [Ne ii], [S iv], [Ne iii], [O iv], [Ne v]) of the ionized gas. SBS 0335-052 E MIR emission is characterized by a bright point source, located in one of the youngest and most embedded stellar clusters (t ∼ 3 Myr, A V  ∼ 15), and underlying extended high-ionization emission (i.e., [O iv] and [Ne v]) from the surroundings of the older and less dusty stellar clusters (t < 20 Myr, A V  ∼ 8). From a comparison with state-of-the-art models, we can exclude shocks, X-ray binaries, and old stellar populations as the main sources of ionization. Interestingly, a 4%–8% contribution of a ∼105 M ⊙intermediate massive black hole (IMBH) is needed to justify the strong [Ne v]/[Ne ii] and would be consistent with optical/UV line ratios from previous studies. However, even IMBH models cannot explain the strongest [O iv]/[Ne iii]. Also, star-forming models (regardless of including X-ray binaries) struggle to reproduce even the lower ionization line ratios (e.g., [S iv]/[Ne ii]) typically observed in BCDs. Overall, while current models suggest the need to account for an accreting IMBH in this high-z analog, limitations still exist in predicting high-ionization emission lines (I.P. > 54 eV) when modeling these low-metallicity environments, and thus other sources of ionization cannot be fully ruled out.

We prove the existence of three non-round, non-isometric Einstein metrics with positive scalar curvature on the sphere S^{10} . Previously, the only even-dimensional spheres known to admit non-round Einstein metrics were S^{6} and S^{8} .

Molten salts have been recently used as catalysts for methane pyrolysis to generate hydrogen and carbon. It was found that molten alkali chlorides, which are poor catalysts, become rather active upon the addition of a small amount of FeCl3. Calculations have shown that this takes place through an unusual mechanism. Due to fluctuations in the position of the ions, the charge on the iron fluctuates between Fe3+ and Fe2+. The electron required for forming Fe2+ is donated by several chlorine ions, and this causes them to be active in breaking the carbon hydrogen bond in methane. It was suggested that this mechanism is general: it takes place whenever the dopant is such that a lower charge state is possible. We test this hypothesis here by examining KCl doped with MoCl5, MoCl4, or MoCl3. We find that MoCl5 and MoCl4 activate KCl by the mechanism described above. MoCl3 does not because Mo3+ is not converted by fluctuations to Mo2+. We also show that the gas-phase dissociation energy of molybdenum chloride can be used as a descriptor to assess its ability to activate methane. Because it is easy to remove one Cl from MoCl5 or MoCl4, they are effective dopants for methane activation. The energy required for the dissociation of MoCl3 is very high, and doping with MoCl3 does not improve catalytic activity.

Abstract: We discuss our transient search for directed energy systems in local galaxies, with calculations indicating the ability of modest searches to detect optical Search for Extraterrestrial Intelligence sources in the closest galaxies. Our analysis follows P. Lubin, where a messenger civilization follows a beacon strategy we call “intelligent targeting.” We plot the required laser time to achieve a signal-to-noise ratio of 10 and find the time for a blind transmission to target all stars in the Milky Way to be achievable for local galactic civilizations. As high cadence and sky coverage is the pathway to enable such a detection, we operate the Local Galactic Transient Survey (LGTS) targeting M31 (the Andromeda galaxy), the Large Magellanic Cloud, and the Small Magellanic Cloud via Las Cumbres Observatory’s network of 0.4 m telescopes. We explore the ability of modest searches like the LGTS to detect directed pulses in optical and near-infrared wavelengths from extraterrestrial intelligence at these distances, and conclude that a civilization utilizing less powerful laser technology than we can construct in this century is readily detectable with the LGTS’s observational capabilities. Data processing of 30,000 LGTS images spanning 5 yr is in progress with the TRansient Image Processing Pipeline.